1. Field of the Invention
This invention relates to a display device for a motor vehicle which permits a displayed image of a light emitting source as a virtual image to be visually recognized on a combiner arranged in front of an eye point of a driver.
2. Description of the Related Art
In some cases, the motor vehicle adopts a virtual-image type display device as disclosed in J-UM-64-33435 and J-UM-64-37735. The virtual-image type display device includes a virtual-image display type combination meter which permits a real image of a meter within a dashboard and a virtual image of another meter to be visually recognized as a single meter unit using a semitransparent panel such as a half mirror fit in a front opening of the dashboard, and a head-up display which causes a virtual image of the displayed image by a light-emitting indicator within a dashboard to be displayed on a combiner or front glass arranged above the dashboard and to be visually recognized in superposition on the front scene of the vehicle beyond the combiner or front glass.
The virtual-image display type combination meter is required to limit the brightness outside the semitransparent panel to a certain degree so that the real image of the meter within the dashboard can be visually recognized through the semitransparent panel. For this purpose, a hood for preventing external light from being projected onto a semitransparent panel must be protruded from the upper edge of the dashboard. Correspondingly, the dashboard is inevitably increased in size and complicated in structure.
On the other hand, the head-up display premises that the combiner or front glass on which external light is projected is used as a screen for displaying the virtual image so that the light emitting source emits the displayed image with a large quantity of light. The head-up display, therefore, does not require a measure for interrupting the external light unlike the virtual-image display type combination meter.
However, the head-up display intends to permit various kinds of information of a vehicle to be visually recognized without moving one""s eyes directed forward to an existing combination meter. Therefore, the virtual image of the displayed image by the light emitting indicator is displayed at a position apart from the combination meter. Thus, unlike the virtual image type combination meter, the head-up display cannot permit a real image of a meter and a virtual image of another meter to be visually recognized as a single meter unit.
In view of the above circumstance, this invention has been accomplished.
An object of this invention is to provide a display device for a motor vehicle which can realize a display with a sense of unity between a real image and a virtual image while avoiding an increase of a dashboard in size and complication thereof in structure.
In order to attain the above object, in accordance with this invention, there is provided a display device for a motor vehicle comprising:
a first light-emitting display source for providing a first displayed image, arranged internally in the motor vehicle;
a combiner for reflecting image light of the first displayed image toward an eye point of a driver of the motor vehicle, a virtual image of the first displayed image which can be visually recognized from the eye point being displayed on the combiner; and
a meter unit for displaying a status of the vehicle as a real image, the meter unit being located between the combiner and the eye point at a position outside an optical path of the image light of the first displayed image, wherein
the combiner has a contour which can be visually recognized from the eye point and nearly surrounds the virtual image and the real image of the meter unit.
In accordance with this configuration, since the contour of the combiner is visually recognized to nearly surround a virtual image of the first displayed image which can be visually recognized from the eye point and a real image of the meter unit being located between the combiner and the eye point at a position outside an optical path of the image light of the first displayed image, the virtual image of the first displayed image and the real image of the meter unit can be visually recognized as combination display by a single meter unit.
Since the meter arranged at a position nearer than the combiner to the eye point is visually recognized directly as a real image from the eye point, as long as the image light of the first displayed image from the first light-emitting display source has the quantity of light approximately equal to the case of a head-up display, there is no necessity of providing a hood for intercepting external light to assure contrast of the first displayed image of the meter as in the case where the light-emitting displayed image of the meter is visually recognized as a real image through the combiner.
In a preferred embodiment of this invention, a plurality of meter units are provided apart from one another in a vehicle width direction, and a portion of the combiner which is located between the adjacent meter units reflects the image light of the first displayed image toward the eye point.
In accordance with such a configuration, since a portion of the combiner which is located between the adjacent meter units reflects the image light of the fist displayed image toward the eye point, the virtual image of the displayed image on the combiner and the real image of the meter which are visually recognized from the eye point are arranged side by side in the vehicle width direction.
In a preferred embodiment of this invention, a steering wheel is arranged at a position nearer than the combiner to the eye point, and the combiner has an upper edge in a positive arc whose curvature differs according to a parallax corresponding to a location difference between the combiner and the steering wheel from the eye point.
In accordance with such a configuration, the contour of the combiner is hidden by the steering wheel so that it cannot be visually recognized from the eye point.
In a preferred embodiment of this embodiment, the combiner is made of a material capable of transmitting light,
a second light-emitting display source for providing a second displayed image representative of another status of the vehicle is arranged in front of the combiner in a longitudinal direction of the vehicle at a position opposite to the eye point with respect to the combiner, the second light-emitting display source providing the second displayed image so that its image light passes a prescribed region of the combiner and reaches the eye point without being intercepted by the meter unit, and
the combiner is located to reflect the image light of the second displayed image toward the eye point in a region exclusive of the prescribed region of the combiner.
In accordance with such a configuration, a second displayed image displayed on the second light-emitting display source arranged in front of the combiner in a longitudinal direction of the vehicle at a position opposite to the eye point with respect to the combiner is visually recognized through a prescribed region, and a virtual image of the displayed image is visually recognized in a region exclusive of the prescribed region of the combiner in which the field of view is not intercepted by the meter.
In a preferred embodiment of this invention, the image displayed by the first light-emitting display source is displayed using one of P-polarized light and S-polarized light, the combiner is provided with a first polarizing plate for intercepting the light component, and a second polarizing plate for intercepting the remaining polarized light is provided between the first light-emitting display source and the combiner.
In accordance with such a configuration, the first image displayed by the first light-emitting display source is displayed using one of P-polarized light and S-polarized light. Since the remaining polarized light is intercepted by the second polarizing plate arranged between the light-emitting display source and the combiner, the image light of the first displayed image which travels from the first light-emitting source passes the second polarizing plate without being intercepted. The image light reaches the inner face subjected to half mirror processing of the combiner and is reflected toward the eye point.
Where the incident external light passes, the inside of the combiner prior to passing the second polarizing plate, either the P-polarized light or S-polarized light is intercepted by the first polarizing plate and only the remaining polarized light is emitted from the combiner. The emitted light reaches the second polarizing plate arranged between the combiner and the light-emitting display source.
Since the remaining polarized light is intercepted by the second polarizing plate, where the external light through the front glass passes the inside of the combiner, it is entirely intercepted before it reaches the light-emitting display source.
In a preferred embodiment of this invention, the second polarizing plate has a surface facing the combiner which is subjected to reflection inhibiting processing whereby reflection of light applied to the surface toward the combiner is inhibited.
In accordance with such a configuration, when the remaining polarized light of the incident external light passed the first polarizing plate reaches the second polarizing plate, although it has lower reflectance than that of the one polarized light, it is reflected toward the combiner. At least a part of the reflected light is reflected toward the eye point by the combiner.
However, since the reflection of the light reached the second polarizing plate toward the combiner is suppressed by the reflection suppressing processing applied to the surface of the second polarizing plate, the quantity of light reflected toward the eye point is reduced.
The above and other objects and features of this invention will be more apparent from the following description taken in conjunction with the accompanying drawings.